Patrick Tew, 18, has spent the past five years studying for a place at Oxbridge. He was planning to decide which university to apply to, and what course to take, during a well-earned gap year.

Instead, the summer will be blighted by the fear that a flawed A-level physics paper may have cost him his chance of an Oxbridge place.

The paper set by the OCR and taken by nearly 8,000 students on Tuesday morning gave a measurement in centimetres in the wording of a question and metres in the accompanying diagram. Tew, a pupil at St Peter and St Paul high school in Lincoln, said: "There were a series of questions and one of them required you to use the length in a calculation.

"It's a 105-minute exam, worth 100 marks, so it's almost a minute a mark. There is no downtime at all.

"I remember looking at the question thinking, that doesn't seem right. I spent time on that when I should have been checking through the rest of the paper to find other questions.

"When I talked to my friends afterwards I found out these questions I didn't [answer] were really easy. It throws your confidence. Time is so precious in an exam.

"If I don't get an A* I'm definitely challenging it. I got 100% in the end of year exam last year."